xref: /freebsd/crypto/openssl/ssl/ssl_sess.c (revision 3eeb75112272ef9ef244a00bc73beef3a146856a)
1 /* ssl/ssl_sess.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3  * All rights reserved.
4  *
5  * This package is an SSL implementation written
6  * by Eric Young (eay@cryptsoft.com).
7  * The implementation was written so as to conform with Netscapes SSL.
8  *
9  * This library is free for commercial and non-commercial use as long as
10  * the following conditions are aheared to.  The following conditions
11  * apply to all code found in this distribution, be it the RC4, RSA,
12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13  * included with this distribution is covered by the same copyright terms
14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15  *
16  * Copyright remains Eric Young's, and as such any Copyright notices in
17  * the code are not to be removed.
18  * If this package is used in a product, Eric Young should be given attribution
19  * as the author of the parts of the library used.
20  * This can be in the form of a textual message at program startup or
21  * in documentation (online or textual) provided with the package.
22  *
23  * Redistribution and use in source and binary forms, with or without
24  * modification, are permitted provided that the following conditions
25  * are met:
26  * 1. Redistributions of source code must retain the copyright
27  *    notice, this list of conditions and the following disclaimer.
28  * 2. Redistributions in binary form must reproduce the above copyright
29  *    notice, this list of conditions and the following disclaimer in the
30  *    documentation and/or other materials provided with the distribution.
31  * 3. All advertising materials mentioning features or use of this software
32  *    must display the following acknowledgement:
33  *    "This product includes cryptographic software written by
34  *     Eric Young (eay@cryptsoft.com)"
35  *    The word 'cryptographic' can be left out if the rouines from the library
36  *    being used are not cryptographic related :-).
37  * 4. If you include any Windows specific code (or a derivative thereof) from
38  *    the apps directory (application code) you must include an acknowledgement:
39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40  *
41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51  * SUCH DAMAGE.
52  *
53  * The licence and distribution terms for any publically available version or
54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
55  * copied and put under another distribution licence
56  * [including the GNU Public Licence.]
57  */
58 /* ====================================================================
59  * Copyright (c) 1998-2006 The OpenSSL Project.  All rights reserved.
60  *
61  * Redistribution and use in source and binary forms, with or without
62  * modification, are permitted provided that the following conditions
63  * are met:
64  *
65  * 1. Redistributions of source code must retain the above copyright
66  *    notice, this list of conditions and the following disclaimer.
67  *
68  * 2. Redistributions in binary form must reproduce the above copyright
69  *    notice, this list of conditions and the following disclaimer in
70  *    the documentation and/or other materials provided with the
71  *    distribution.
72  *
73  * 3. All advertising materials mentioning features or use of this
74  *    software must display the following acknowledgment:
75  *    "This product includes software developed by the OpenSSL Project
76  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
77  *
78  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79  *    endorse or promote products derived from this software without
80  *    prior written permission. For written permission, please contact
81  *    openssl-core@openssl.org.
82  *
83  * 5. Products derived from this software may not be called "OpenSSL"
84  *    nor may "OpenSSL" appear in their names without prior written
85  *    permission of the OpenSSL Project.
86  *
87  * 6. Redistributions of any form whatsoever must retain the following
88  *    acknowledgment:
89  *    "This product includes software developed by the OpenSSL Project
90  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
91  *
92  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
96  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103  * OF THE POSSIBILITY OF SUCH DAMAGE.
104  * ====================================================================
105  *
106  * This product includes cryptographic software written by Eric Young
107  * (eay@cryptsoft.com).  This product includes software written by Tim
108  * Hudson (tjh@cryptsoft.com).
109  *
110  */
111 /* ====================================================================
112  * Copyright 2005 Nokia. All rights reserved.
113  *
114  * The portions of the attached software ("Contribution") is developed by
115  * Nokia Corporation and is licensed pursuant to the OpenSSL open source
116  * license.
117  *
118  * The Contribution, originally written by Mika Kousa and Pasi Eronen of
119  * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
120  * support (see RFC 4279) to OpenSSL.
121  *
122  * No patent licenses or other rights except those expressly stated in
123  * the OpenSSL open source license shall be deemed granted or received
124  * expressly, by implication, estoppel, or otherwise.
125  *
126  * No assurances are provided by Nokia that the Contribution does not
127  * infringe the patent or other intellectual property rights of any third
128  * party or that the license provides you with all the necessary rights
129  * to make use of the Contribution.
130  *
131  * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
132  * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
133  * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
134  * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
135  * OTHERWISE.
136  */
137 
138 #include <stdio.h>
139 #include <openssl/lhash.h>
140 #include <openssl/rand.h>
141 #ifndef OPENSSL_NO_ENGINE
142 # include <openssl/engine.h>
143 #endif
144 #include "ssl_locl.h"
145 
146 static void SSL_SESSION_list_remove(SSL_CTX *ctx, SSL_SESSION *s);
147 static void SSL_SESSION_list_add(SSL_CTX *ctx, SSL_SESSION *s);
148 static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck);
149 
150 SSL_SESSION *SSL_get_session(const SSL *ssl)
151 /* aka SSL_get0_session; gets 0 objects, just returns a copy of the pointer */
152 {
153     return (ssl->session);
154 }
155 
156 SSL_SESSION *SSL_get1_session(SSL *ssl)
157 /* variant of SSL_get_session: caller really gets something */
158 {
159     SSL_SESSION *sess;
160     /*
161      * Need to lock this all up rather than just use CRYPTO_add so that
162      * somebody doesn't free ssl->session between when we check it's non-null
163      * and when we up the reference count.
164      */
165     CRYPTO_w_lock(CRYPTO_LOCK_SSL_SESSION);
166     sess = ssl->session;
167     if (sess)
168         sess->references++;
169     CRYPTO_w_unlock(CRYPTO_LOCK_SSL_SESSION);
170     return (sess);
171 }
172 
173 int SSL_SESSION_get_ex_new_index(long argl, void *argp,
174                                  CRYPTO_EX_new *new_func,
175                                  CRYPTO_EX_dup *dup_func,
176                                  CRYPTO_EX_free *free_func)
177 {
178     return CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_SSL_SESSION, argl, argp,
179                                    new_func, dup_func, free_func);
180 }
181 
182 int SSL_SESSION_set_ex_data(SSL_SESSION *s, int idx, void *arg)
183 {
184     return (CRYPTO_set_ex_data(&s->ex_data, idx, arg));
185 }
186 
187 void *SSL_SESSION_get_ex_data(const SSL_SESSION *s, int idx)
188 {
189     return (CRYPTO_get_ex_data(&s->ex_data, idx));
190 }
191 
192 SSL_SESSION *SSL_SESSION_new(void)
193 {
194     SSL_SESSION *ss;
195 
196     ss = (SSL_SESSION *)OPENSSL_malloc(sizeof(SSL_SESSION));
197     if (ss == NULL) {
198         SSLerr(SSL_F_SSL_SESSION_NEW, ERR_R_MALLOC_FAILURE);
199         return (0);
200     }
201     memset(ss, 0, sizeof(SSL_SESSION));
202 
203     ss->verify_result = 1;      /* avoid 0 (= X509_V_OK) just in case */
204     ss->references = 1;
205     ss->timeout = 60 * 5 + 4;   /* 5 minute timeout by default */
206     ss->time = (unsigned long)time(NULL);
207     ss->prev = NULL;
208     ss->next = NULL;
209     ss->compress_meth = 0;
210 #ifndef OPENSSL_NO_TLSEXT
211     ss->tlsext_hostname = NULL;
212 # ifndef OPENSSL_NO_EC
213     ss->tlsext_ecpointformatlist_length = 0;
214     ss->tlsext_ecpointformatlist = NULL;
215     ss->tlsext_ellipticcurvelist_length = 0;
216     ss->tlsext_ellipticcurvelist = NULL;
217 # endif
218 #endif
219     CRYPTO_new_ex_data(CRYPTO_EX_INDEX_SSL_SESSION, ss, &ss->ex_data);
220 #ifndef OPENSSL_NO_PSK
221     ss->psk_identity_hint = NULL;
222     ss->psk_identity = NULL;
223 #endif
224 #ifndef OPENSSL_NO_SRP
225     ss->srp_username = NULL;
226 #endif
227     return (ss);
228 }
229 
230 /*
231  * Create a new SSL_SESSION and duplicate the contents of |src| into it. If
232  * ticket == 0 then no ticket information is duplicated, otherwise it is.
233  */
234 SSL_SESSION *ssl_session_dup(SSL_SESSION *src, int ticket)
235 {
236     SSL_SESSION *dest;
237 
238     dest = OPENSSL_malloc(sizeof(*src));
239     if (dest == NULL) {
240         goto err;
241     }
242     memcpy(dest, src, sizeof(*dest));
243 
244     /*
245      * Set the various pointers to NULL so that we can call SSL_SESSION_free in
246      * the case of an error whilst halfway through constructing dest
247      */
248 #ifndef OPENSSL_NO_PSK
249     dest->psk_identity_hint = NULL;
250     dest->psk_identity = NULL;
251 #endif
252     dest->ciphers = NULL;
253 #ifndef OPENSSL_NO_TLSEXT
254     dest->tlsext_hostname = NULL;
255 # ifndef OPENSSL_NO_EC
256     dest->tlsext_ecpointformatlist = NULL;
257     dest->tlsext_ellipticcurvelist = NULL;
258 # endif
259     dest->tlsext_tick = NULL;
260 #endif
261 #ifndef OPENSSL_NO_SRP
262     dest->srp_username = NULL;
263 #endif
264 
265     /* We deliberately don't copy the prev and next pointers */
266     dest->prev = NULL;
267     dest->next = NULL;
268 
269     dest->references = 1;
270 
271     if (src->sess_cert != NULL)
272         CRYPTO_add(&src->sess_cert->references, 1, CRYPTO_LOCK_SSL_SESS_CERT);
273 
274     if (src->peer != NULL)
275         CRYPTO_add(&src->peer->references, 1, CRYPTO_LOCK_X509);
276 
277     if (!CRYPTO_new_ex_data(CRYPTO_EX_INDEX_SSL_SESSION, dest, &dest->ex_data))
278         goto err;
279 
280 #ifndef OPENSSL_NO_PSK
281     if (src->psk_identity_hint) {
282         dest->psk_identity_hint = BUF_strdup(src->psk_identity_hint);
283         if (dest->psk_identity_hint == NULL) {
284             goto err;
285         }
286     }
287     if (src->psk_identity) {
288         dest->psk_identity = BUF_strdup(src->psk_identity);
289         if (dest->psk_identity == NULL) {
290             goto err;
291         }
292     }
293 #endif
294 
295     if(src->ciphers != NULL) {
296         dest->ciphers = sk_SSL_CIPHER_dup(src->ciphers);
297         if (dest->ciphers == NULL)
298             goto err;
299     }
300 
301     if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_SSL_SESSION,
302                                             &dest->ex_data, &src->ex_data)) {
303         goto err;
304     }
305 
306 #ifndef OPENSSL_NO_TLSEXT
307     if (src->tlsext_hostname) {
308         dest->tlsext_hostname = BUF_strdup(src->tlsext_hostname);
309         if (dest->tlsext_hostname == NULL) {
310             goto err;
311         }
312     }
313 # ifndef OPENSSL_NO_EC
314     if (src->tlsext_ecpointformatlist) {
315         dest->tlsext_ecpointformatlist =
316             BUF_memdup(src->tlsext_ecpointformatlist,
317                        src->tlsext_ecpointformatlist_length);
318         if (dest->tlsext_ecpointformatlist == NULL)
319             goto err;
320     }
321     if (src->tlsext_ellipticcurvelist) {
322         dest->tlsext_ellipticcurvelist =
323             BUF_memdup(src->tlsext_ellipticcurvelist,
324                        src->tlsext_ellipticcurvelist_length);
325         if (dest->tlsext_ellipticcurvelist == NULL)
326             goto err;
327     }
328 # endif
329 
330     if (ticket != 0 && src->tlsext_tick != NULL) {
331         dest->tlsext_tick = BUF_memdup(src->tlsext_tick, src->tlsext_ticklen);
332         if(dest->tlsext_tick == NULL)
333             goto err;
334     } else {
335         dest->tlsext_tick_lifetime_hint = 0;
336         dest->tlsext_ticklen = 0;
337     }
338 #endif
339 
340 #ifndef OPENSSL_NO_SRP
341     if (src->srp_username) {
342         dest->srp_username = BUF_strdup(src->srp_username);
343         if (dest->srp_username == NULL) {
344             goto err;
345         }
346     }
347 #endif
348 
349     return dest;
350 err:
351     SSLerr(SSL_F_SSL_SESSION_DUP, ERR_R_MALLOC_FAILURE);
352     SSL_SESSION_free(dest);
353     return NULL;
354 }
355 
356 const unsigned char *SSL_SESSION_get_id(const SSL_SESSION *s,
357                                         unsigned int *len)
358 {
359     if (len)
360         *len = s->session_id_length;
361     return s->session_id;
362 }
363 
364 unsigned int SSL_SESSION_get_compress_id(const SSL_SESSION *s)
365 {
366     return s->compress_meth;
367 }
368 
369 /*
370  * Even with SSLv2, we have 16 bytes (128 bits) of session ID space.
371  * SSLv3/TLSv1 has 32 bytes (256 bits). As such, filling the ID with random
372  * gunk repeatedly until we have no conflict is going to complete in one
373  * iteration pretty much "most" of the time (btw: understatement). So, if it
374  * takes us 10 iterations and we still can't avoid a conflict - well that's a
375  * reasonable point to call it quits. Either the RAND code is broken or
376  * someone is trying to open roughly very close to 2^128 (or 2^256) SSL
377  * sessions to our server. How you might store that many sessions is perhaps
378  * a more interesting question ...
379  */
380 
381 #define MAX_SESS_ID_ATTEMPTS 10
382 static int def_generate_session_id(const SSL *ssl, unsigned char *id,
383                                    unsigned int *id_len)
384 {
385     unsigned int retry = 0;
386     do
387         if (RAND_bytes(id, *id_len) <= 0)
388             return 0;
389     while (SSL_has_matching_session_id(ssl, id, *id_len) &&
390            (++retry < MAX_SESS_ID_ATTEMPTS)) ;
391     if (retry < MAX_SESS_ID_ATTEMPTS)
392         return 1;
393     /* else - woops a session_id match */
394     /*
395      * XXX We should also check the external cache -- but the probability of
396      * a collision is negligible, and we could not prevent the concurrent
397      * creation of sessions with identical IDs since we currently don't have
398      * means to atomically check whether a session ID already exists and make
399      * a reservation for it if it does not (this problem applies to the
400      * internal cache as well).
401      */
402     return 0;
403 }
404 
405 int ssl_get_new_session(SSL *s, int session)
406 {
407     /* This gets used by clients and servers. */
408 
409     unsigned int tmp;
410     SSL_SESSION *ss = NULL;
411     GEN_SESSION_CB cb = def_generate_session_id;
412 
413     if ((ss = SSL_SESSION_new()) == NULL)
414         return (0);
415 
416     /* If the context has a default timeout, use it */
417     if (s->session_ctx->session_timeout == 0)
418         ss->timeout = SSL_get_default_timeout(s);
419     else
420         ss->timeout = s->session_ctx->session_timeout;
421 
422     if (s->session != NULL) {
423         SSL_SESSION_free(s->session);
424         s->session = NULL;
425     }
426 
427     if (session) {
428         if (s->version == SSL2_VERSION) {
429             ss->ssl_version = SSL2_VERSION;
430             ss->session_id_length = SSL2_SSL_SESSION_ID_LENGTH;
431         } else if (s->version == SSL3_VERSION) {
432             ss->ssl_version = SSL3_VERSION;
433             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
434         } else if (s->version == TLS1_VERSION) {
435             ss->ssl_version = TLS1_VERSION;
436             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
437         } else if (s->version == TLS1_1_VERSION) {
438             ss->ssl_version = TLS1_1_VERSION;
439             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
440         } else if (s->version == TLS1_2_VERSION) {
441             ss->ssl_version = TLS1_2_VERSION;
442             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
443         } else if (s->version == DTLS1_BAD_VER) {
444             ss->ssl_version = DTLS1_BAD_VER;
445             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
446         } else if (s->version == DTLS1_VERSION) {
447             ss->ssl_version = DTLS1_VERSION;
448             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
449         } else if (s->version == DTLS1_2_VERSION) {
450             ss->ssl_version = DTLS1_2_VERSION;
451             ss->session_id_length = SSL3_SSL_SESSION_ID_LENGTH;
452         } else {
453             SSLerr(SSL_F_SSL_GET_NEW_SESSION, SSL_R_UNSUPPORTED_SSL_VERSION);
454             SSL_SESSION_free(ss);
455             return (0);
456         }
457 #ifndef OPENSSL_NO_TLSEXT
458         /*-
459          * If RFC5077 ticket, use empty session ID (as server).
460          * Note that:
461          * (a) ssl_get_prev_session() does lookahead into the
462          *     ClientHello extensions to find the session ticket.
463          *     When ssl_get_prev_session() fails, s3_srvr.c calls
464          *     ssl_get_new_session() in ssl3_get_client_hello().
465          *     At that point, it has not yet parsed the extensions,
466          *     however, because of the lookahead, it already knows
467          *     whether a ticket is expected or not.
468          *
469          * (b) s3_clnt.c calls ssl_get_new_session() before parsing
470          *     ServerHello extensions, and before recording the session
471          *     ID received from the server, so this block is a noop.
472          */
473         if (s->tlsext_ticket_expected) {
474             ss->session_id_length = 0;
475             goto sess_id_done;
476         }
477 #endif
478         /* Choose which callback will set the session ID */
479         CRYPTO_r_lock(CRYPTO_LOCK_SSL_CTX);
480         if (s->generate_session_id)
481             cb = s->generate_session_id;
482         else if (s->session_ctx->generate_session_id)
483             cb = s->session_ctx->generate_session_id;
484         CRYPTO_r_unlock(CRYPTO_LOCK_SSL_CTX);
485         /* Choose a session ID */
486         tmp = ss->session_id_length;
487         if (!cb(s, ss->session_id, &tmp)) {
488             /* The callback failed */
489             SSLerr(SSL_F_SSL_GET_NEW_SESSION,
490                    SSL_R_SSL_SESSION_ID_CALLBACK_FAILED);
491             SSL_SESSION_free(ss);
492             return (0);
493         }
494         /*
495          * Don't allow the callback to set the session length to zero. nor
496          * set it higher than it was.
497          */
498         if (!tmp || (tmp > ss->session_id_length)) {
499             /* The callback set an illegal length */
500             SSLerr(SSL_F_SSL_GET_NEW_SESSION,
501                    SSL_R_SSL_SESSION_ID_HAS_BAD_LENGTH);
502             SSL_SESSION_free(ss);
503             return (0);
504         }
505         /* If the session length was shrunk and we're SSLv2, pad it */
506         if ((tmp < ss->session_id_length) && (s->version == SSL2_VERSION))
507             memset(ss->session_id + tmp, 0, ss->session_id_length - tmp);
508         else
509             ss->session_id_length = tmp;
510         /* Finally, check for a conflict */
511         if (SSL_has_matching_session_id(s, ss->session_id,
512                                         ss->session_id_length)) {
513             SSLerr(SSL_F_SSL_GET_NEW_SESSION, SSL_R_SSL_SESSION_ID_CONFLICT);
514             SSL_SESSION_free(ss);
515             return (0);
516         }
517 #ifndef OPENSSL_NO_TLSEXT
518  sess_id_done:
519         if (s->tlsext_hostname) {
520             ss->tlsext_hostname = BUF_strdup(s->tlsext_hostname);
521             if (ss->tlsext_hostname == NULL) {
522                 SSLerr(SSL_F_SSL_GET_NEW_SESSION, ERR_R_INTERNAL_ERROR);
523                 SSL_SESSION_free(ss);
524                 return 0;
525             }
526         }
527 #endif
528     } else {
529         ss->session_id_length = 0;
530     }
531 
532     if (s->sid_ctx_length > sizeof(ss->sid_ctx)) {
533         SSLerr(SSL_F_SSL_GET_NEW_SESSION, ERR_R_INTERNAL_ERROR);
534         SSL_SESSION_free(ss);
535         return 0;
536     }
537     memcpy(ss->sid_ctx, s->sid_ctx, s->sid_ctx_length);
538     ss->sid_ctx_length = s->sid_ctx_length;
539     s->session = ss;
540     ss->ssl_version = s->version;
541     ss->verify_result = X509_V_OK;
542 
543     return (1);
544 }
545 
546 /*-
547  * ssl_get_prev attempts to find an SSL_SESSION to be used to resume this
548  * connection. It is only called by servers.
549  *
550  *   session_id: points at the session ID in the ClientHello. This code will
551  *       read past the end of this in order to parse out the session ticket
552  *       extension, if any.
553  *   len: the length of the session ID.
554  *   limit: a pointer to the first byte after the ClientHello.
555  *
556  * Returns:
557  *   -1: error
558  *    0: a session may have been found.
559  *
560  * Side effects:
561  *   - If a session is found then s->session is pointed at it (after freeing an
562  *     existing session if need be) and s->verify_result is set from the session.
563  *   - Both for new and resumed sessions, s->tlsext_ticket_expected is set to 1
564  *     if the server should issue a new session ticket (to 0 otherwise).
565  */
566 int ssl_get_prev_session(SSL *s, unsigned char *session_id, int len,
567                          const unsigned char *limit)
568 {
569     /* This is used only by servers. */
570 
571     SSL_SESSION *ret = NULL;
572     int fatal = 0;
573     int try_session_cache = 1;
574 #ifndef OPENSSL_NO_TLSEXT
575     int r;
576 #endif
577 
578     if (limit - session_id < len) {
579         fatal = 1;
580         goto err;
581     }
582 
583     if (len == 0)
584         try_session_cache = 0;
585 
586 #ifndef OPENSSL_NO_TLSEXT
587     /* sets s->tlsext_ticket_expected */
588     r = tls1_process_ticket(s, session_id, len, limit, &ret);
589     switch (r) {
590     case -1:                   /* Error during processing */
591         fatal = 1;
592         goto err;
593     case 0:                    /* No ticket found */
594     case 1:                    /* Zero length ticket found */
595         break;                  /* Ok to carry on processing session id. */
596     case 2:                    /* Ticket found but not decrypted. */
597     case 3:                    /* Ticket decrypted, *ret has been set. */
598         try_session_cache = 0;
599         break;
600     default:
601         abort();
602     }
603 #endif
604 
605     if (try_session_cache &&
606         ret == NULL &&
607         !(s->session_ctx->session_cache_mode &
608           SSL_SESS_CACHE_NO_INTERNAL_LOOKUP)) {
609         SSL_SESSION data;
610         data.ssl_version = s->version;
611         data.session_id_length = len;
612         if (len == 0)
613             return 0;
614         memcpy(data.session_id, session_id, len);
615         CRYPTO_r_lock(CRYPTO_LOCK_SSL_CTX);
616         ret = lh_SSL_SESSION_retrieve(s->session_ctx->sessions, &data);
617         if (ret != NULL) {
618             /* don't allow other threads to steal it: */
619             CRYPTO_add(&ret->references, 1, CRYPTO_LOCK_SSL_SESSION);
620         }
621         CRYPTO_r_unlock(CRYPTO_LOCK_SSL_CTX);
622         if (ret == NULL)
623             s->session_ctx->stats.sess_miss++;
624     }
625 
626     if (try_session_cache &&
627         ret == NULL && s->session_ctx->get_session_cb != NULL) {
628         int copy = 1;
629 
630         if ((ret = s->session_ctx->get_session_cb(s, session_id, len, &copy))) {
631             s->session_ctx->stats.sess_cb_hit++;
632 
633             /*
634              * Increment reference count now if the session callback asks us
635              * to do so (note that if the session structures returned by the
636              * callback are shared between threads, it must handle the
637              * reference count itself [i.e. copy == 0], or things won't be
638              * thread-safe).
639              */
640             if (copy)
641                 CRYPTO_add(&ret->references, 1, CRYPTO_LOCK_SSL_SESSION);
642 
643             /*
644              * Add the externally cached session to the internal cache as
645              * well if and only if we are supposed to.
646              */
647             if (!
648                 (s->session_ctx->session_cache_mode &
649                  SSL_SESS_CACHE_NO_INTERNAL_STORE))
650                 /*
651                  * The following should not return 1, otherwise, things are
652                  * very strange
653                  */
654                 SSL_CTX_add_session(s->session_ctx, ret);
655         }
656     }
657 
658     if (ret == NULL)
659         goto err;
660 
661     /* Now ret is non-NULL and we own one of its reference counts. */
662 
663     if (ret->sid_ctx_length != s->sid_ctx_length
664         || memcmp(ret->sid_ctx, s->sid_ctx, ret->sid_ctx_length)) {
665         /*
666          * We have the session requested by the client, but we don't want to
667          * use it in this context.
668          */
669         goto err;               /* treat like cache miss */
670     }
671 
672     if ((s->verify_mode & SSL_VERIFY_PEER) && s->sid_ctx_length == 0) {
673         /*
674          * We can't be sure if this session is being used out of context,
675          * which is especially important for SSL_VERIFY_PEER. The application
676          * should have used SSL[_CTX]_set_session_id_context. For this error
677          * case, we generate an error instead of treating the event like a
678          * cache miss (otherwise it would be easy for applications to
679          * effectively disable the session cache by accident without anyone
680          * noticing).
681          */
682 
683         SSLerr(SSL_F_SSL_GET_PREV_SESSION,
684                SSL_R_SESSION_ID_CONTEXT_UNINITIALIZED);
685         fatal = 1;
686         goto err;
687     }
688 
689     if (ret->cipher == NULL) {
690         unsigned char buf[5], *p;
691         unsigned long l;
692 
693         p = buf;
694         l = ret->cipher_id;
695         l2n(l, p);
696         if ((ret->ssl_version >> 8) >= SSL3_VERSION_MAJOR)
697             ret->cipher = ssl_get_cipher_by_char(s, &(buf[2]));
698         else
699             ret->cipher = ssl_get_cipher_by_char(s, &(buf[1]));
700         if (ret->cipher == NULL)
701             goto err;
702     }
703 
704     if (ret->timeout < (long)(time(NULL) - ret->time)) { /* timeout */
705         s->session_ctx->stats.sess_timeout++;
706         if (try_session_cache) {
707             /* session was from the cache, so remove it */
708             SSL_CTX_remove_session(s->session_ctx, ret);
709         }
710         goto err;
711     }
712 
713     s->session_ctx->stats.sess_hit++;
714 
715     if (s->session != NULL)
716         SSL_SESSION_free(s->session);
717     s->session = ret;
718     s->verify_result = s->session->verify_result;
719     return 1;
720 
721  err:
722     if (ret != NULL) {
723         SSL_SESSION_free(ret);
724 #ifndef OPENSSL_NO_TLSEXT
725         if (!try_session_cache) {
726             /*
727              * The session was from a ticket, so we should issue a ticket for
728              * the new session
729              */
730             s->tlsext_ticket_expected = 1;
731         }
732 #endif
733     }
734     if (fatal)
735         return -1;
736     else
737         return 0;
738 }
739 
740 int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c)
741 {
742     int ret = 0;
743     SSL_SESSION *s;
744 
745     /*
746      * add just 1 reference count for the SSL_CTX's session cache even though
747      * it has two ways of access: each session is in a doubly linked list and
748      * an lhash
749      */
750     CRYPTO_add(&c->references, 1, CRYPTO_LOCK_SSL_SESSION);
751     /*
752      * if session c is in already in cache, we take back the increment later
753      */
754 
755     CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
756     s = lh_SSL_SESSION_insert(ctx->sessions, c);
757 
758     /*
759      * s != NULL iff we already had a session with the given PID. In this
760      * case, s == c should hold (then we did not really modify
761      * ctx->sessions), or we're in trouble.
762      */
763     if (s != NULL && s != c) {
764         /* We *are* in trouble ... */
765         SSL_SESSION_list_remove(ctx, s);
766         SSL_SESSION_free(s);
767         /*
768          * ... so pretend the other session did not exist in cache (we cannot
769          * handle two SSL_SESSION structures with identical session ID in the
770          * same cache, which could happen e.g. when two threads concurrently
771          * obtain the same session from an external cache)
772          */
773         s = NULL;
774     } else if (s == NULL &&
775                lh_SSL_SESSION_retrieve(ctx->sessions, c) == NULL) {
776         /* s == NULL can also mean OOM error in lh_SSL_SESSION_insert ... */
777 
778         /*
779          * ... so take back the extra reference and also don't add
780          * the session to the SSL_SESSION_list at this time
781          */
782         s = c;
783     }
784 
785     /* Put at the head of the queue unless it is already in the cache */
786     if (s == NULL)
787         SSL_SESSION_list_add(ctx, c);
788 
789     if (s != NULL) {
790         /*
791          * existing cache entry -- decrement previously incremented reference
792          * count because it already takes into account the cache
793          */
794 
795         SSL_SESSION_free(s);    /* s == c */
796         ret = 0;
797     } else {
798         /*
799          * new cache entry -- remove old ones if cache has become too large
800          */
801 
802         ret = 1;
803 
804         if (SSL_CTX_sess_get_cache_size(ctx) > 0) {
805             while (SSL_CTX_sess_number(ctx) >
806                    SSL_CTX_sess_get_cache_size(ctx)) {
807                 if (!remove_session_lock(ctx, ctx->session_cache_tail, 0))
808                     break;
809                 else
810                     ctx->stats.sess_cache_full++;
811             }
812         }
813     }
814     CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
815     return (ret);
816 }
817 
818 int SSL_CTX_remove_session(SSL_CTX *ctx, SSL_SESSION *c)
819 {
820     return remove_session_lock(ctx, c, 1);
821 }
822 
823 static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck)
824 {
825     SSL_SESSION *r;
826     int ret = 0;
827 
828     if ((c != NULL) && (c->session_id_length != 0)) {
829         if (lck)
830             CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
831         if ((r = lh_SSL_SESSION_retrieve(ctx->sessions, c)) == c) {
832             ret = 1;
833             r = lh_SSL_SESSION_delete(ctx->sessions, c);
834             SSL_SESSION_list_remove(ctx, c);
835         }
836 
837         if (lck)
838             CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
839 
840         if (ret) {
841             r->not_resumable = 1;
842             if (ctx->remove_session_cb != NULL)
843                 ctx->remove_session_cb(ctx, r);
844             SSL_SESSION_free(r);
845         }
846     } else
847         ret = 0;
848     return (ret);
849 }
850 
851 void SSL_SESSION_free(SSL_SESSION *ss)
852 {
853     int i;
854 
855     if (ss == NULL)
856         return;
857 
858     i = CRYPTO_add(&ss->references, -1, CRYPTO_LOCK_SSL_SESSION);
859 #ifdef REF_PRINT
860     REF_PRINT("SSL_SESSION", ss);
861 #endif
862     if (i > 0)
863         return;
864 #ifdef REF_CHECK
865     if (i < 0) {
866         fprintf(stderr, "SSL_SESSION_free, bad reference count\n");
867         abort();                /* ok */
868     }
869 #endif
870 
871     CRYPTO_free_ex_data(CRYPTO_EX_INDEX_SSL_SESSION, ss, &ss->ex_data);
872 
873     OPENSSL_cleanse(ss->key_arg, sizeof(ss->key_arg));
874     OPENSSL_cleanse(ss->master_key, sizeof(ss->master_key));
875     OPENSSL_cleanse(ss->session_id, sizeof(ss->session_id));
876     if (ss->sess_cert != NULL)
877         ssl_sess_cert_free(ss->sess_cert);
878     if (ss->peer != NULL)
879         X509_free(ss->peer);
880     if (ss->ciphers != NULL)
881         sk_SSL_CIPHER_free(ss->ciphers);
882 #ifndef OPENSSL_NO_TLSEXT
883     if (ss->tlsext_hostname != NULL)
884         OPENSSL_free(ss->tlsext_hostname);
885     if (ss->tlsext_tick != NULL)
886         OPENSSL_free(ss->tlsext_tick);
887 # ifndef OPENSSL_NO_EC
888     ss->tlsext_ecpointformatlist_length = 0;
889     if (ss->tlsext_ecpointformatlist != NULL)
890         OPENSSL_free(ss->tlsext_ecpointformatlist);
891     ss->tlsext_ellipticcurvelist_length = 0;
892     if (ss->tlsext_ellipticcurvelist != NULL)
893         OPENSSL_free(ss->tlsext_ellipticcurvelist);
894 # endif                         /* OPENSSL_NO_EC */
895 #endif
896 #ifndef OPENSSL_NO_PSK
897     if (ss->psk_identity_hint != NULL)
898         OPENSSL_free(ss->psk_identity_hint);
899     if (ss->psk_identity != NULL)
900         OPENSSL_free(ss->psk_identity);
901 #endif
902 #ifndef OPENSSL_NO_SRP
903     if (ss->srp_username != NULL)
904         OPENSSL_free(ss->srp_username);
905 #endif
906     OPENSSL_cleanse(ss, sizeof(*ss));
907     OPENSSL_free(ss);
908 }
909 
910 int SSL_set_session(SSL *s, SSL_SESSION *session)
911 {
912     int ret = 0;
913     const SSL_METHOD *meth;
914 
915     if (session != NULL) {
916         meth = s->ctx->method->get_ssl_method(session->ssl_version);
917         if (meth == NULL)
918             meth = s->method->get_ssl_method(session->ssl_version);
919         if (meth == NULL) {
920             SSLerr(SSL_F_SSL_SET_SESSION, SSL_R_UNABLE_TO_FIND_SSL_METHOD);
921             return (0);
922         }
923 
924         if (meth != s->method) {
925             if (!SSL_set_ssl_method(s, meth))
926                 return (0);
927         }
928 #ifndef OPENSSL_NO_KRB5
929         if (s->kssl_ctx && !s->kssl_ctx->client_princ &&
930             session->krb5_client_princ_len > 0) {
931             s->kssl_ctx->client_princ =
932                 (char *)OPENSSL_malloc(session->krb5_client_princ_len + 1);
933             if (s->kssl_ctx->client_princ == NULL) {
934                 SSLerr(SSL_F_SSL_SET_SESSION, ERR_R_MALLOC_FAILURE);
935                 return 0;
936             }
937             memcpy(s->kssl_ctx->client_princ, session->krb5_client_princ,
938                    session->krb5_client_princ_len);
939             s->kssl_ctx->client_princ[session->krb5_client_princ_len] = '\0';
940         }
941 #endif                          /* OPENSSL_NO_KRB5 */
942 
943         /* CRYPTO_w_lock(CRYPTO_LOCK_SSL); */
944         CRYPTO_add(&session->references, 1, CRYPTO_LOCK_SSL_SESSION);
945         if (s->session != NULL)
946             SSL_SESSION_free(s->session);
947         s->session = session;
948         s->verify_result = s->session->verify_result;
949         /* CRYPTO_w_unlock(CRYPTO_LOCK_SSL); */
950         ret = 1;
951     } else {
952         if (s->session != NULL) {
953             SSL_SESSION_free(s->session);
954             s->session = NULL;
955         }
956 
957         meth = s->ctx->method;
958         if (meth != s->method) {
959             if (!SSL_set_ssl_method(s, meth))
960                 return (0);
961         }
962         ret = 1;
963     }
964     return (ret);
965 }
966 
967 long SSL_SESSION_set_timeout(SSL_SESSION *s, long t)
968 {
969     if (s == NULL)
970         return (0);
971     s->timeout = t;
972     return (1);
973 }
974 
975 long SSL_SESSION_get_timeout(const SSL_SESSION *s)
976 {
977     if (s == NULL)
978         return (0);
979     return (s->timeout);
980 }
981 
982 long SSL_SESSION_get_time(const SSL_SESSION *s)
983 {
984     if (s == NULL)
985         return (0);
986     return (s->time);
987 }
988 
989 long SSL_SESSION_set_time(SSL_SESSION *s, long t)
990 {
991     if (s == NULL)
992         return (0);
993     s->time = t;
994     return (t);
995 }
996 
997 X509 *SSL_SESSION_get0_peer(SSL_SESSION *s)
998 {
999     return s->peer;
1000 }
1001 
1002 int SSL_SESSION_set1_id_context(SSL_SESSION *s, const unsigned char *sid_ctx,
1003                                 unsigned int sid_ctx_len)
1004 {
1005     if (sid_ctx_len > SSL_MAX_SID_CTX_LENGTH) {
1006         SSLerr(SSL_F_SSL_SESSION_SET1_ID_CONTEXT,
1007                SSL_R_SSL_SESSION_ID_CONTEXT_TOO_LONG);
1008         return 0;
1009     }
1010     s->sid_ctx_length = sid_ctx_len;
1011     if (s->sid_ctx != sid_ctx)
1012         memcpy(s->sid_ctx, sid_ctx, sid_ctx_len);
1013 
1014     return 1;
1015 }
1016 
1017 long SSL_CTX_set_timeout(SSL_CTX *s, long t)
1018 {
1019     long l;
1020     if (s == NULL)
1021         return (0);
1022     l = s->session_timeout;
1023     s->session_timeout = t;
1024     return (l);
1025 }
1026 
1027 long SSL_CTX_get_timeout(const SSL_CTX *s)
1028 {
1029     if (s == NULL)
1030         return (0);
1031     return (s->session_timeout);
1032 }
1033 
1034 #ifndef OPENSSL_NO_TLSEXT
1035 int SSL_set_session_secret_cb(SSL *s,
1036                               int (*tls_session_secret_cb) (SSL *s,
1037                                                             void *secret,
1038                                                             int *secret_len,
1039                                                             STACK_OF(SSL_CIPHER)
1040                                                             *peer_ciphers,
1041                                                             SSL_CIPHER
1042                                                             **cipher,
1043                                                             void *arg),
1044                               void *arg)
1045 {
1046     if (s == NULL)
1047         return (0);
1048     s->tls_session_secret_cb = tls_session_secret_cb;
1049     s->tls_session_secret_cb_arg = arg;
1050     return (1);
1051 }
1052 
1053 int SSL_set_session_ticket_ext_cb(SSL *s, tls_session_ticket_ext_cb_fn cb,
1054                                   void *arg)
1055 {
1056     if (s == NULL)
1057         return (0);
1058     s->tls_session_ticket_ext_cb = cb;
1059     s->tls_session_ticket_ext_cb_arg = arg;
1060     return (1);
1061 }
1062 
1063 int SSL_set_session_ticket_ext(SSL *s, void *ext_data, int ext_len)
1064 {
1065     if (s->version >= TLS1_VERSION) {
1066         if (s->tlsext_session_ticket) {
1067             OPENSSL_free(s->tlsext_session_ticket);
1068             s->tlsext_session_ticket = NULL;
1069         }
1070 
1071         s->tlsext_session_ticket =
1072             OPENSSL_malloc(sizeof(TLS_SESSION_TICKET_EXT) + ext_len);
1073         if (!s->tlsext_session_ticket) {
1074             SSLerr(SSL_F_SSL_SET_SESSION_TICKET_EXT, ERR_R_MALLOC_FAILURE);
1075             return 0;
1076         }
1077 
1078         if (ext_data) {
1079             s->tlsext_session_ticket->length = ext_len;
1080             s->tlsext_session_ticket->data = s->tlsext_session_ticket + 1;
1081             memcpy(s->tlsext_session_ticket->data, ext_data, ext_len);
1082         } else {
1083             s->tlsext_session_ticket->length = 0;
1084             s->tlsext_session_ticket->data = NULL;
1085         }
1086 
1087         return 1;
1088     }
1089 
1090     return 0;
1091 }
1092 #endif                          /* OPENSSL_NO_TLSEXT */
1093 
1094 typedef struct timeout_param_st {
1095     SSL_CTX *ctx;
1096     long time;
1097     LHASH_OF(SSL_SESSION) *cache;
1098 } TIMEOUT_PARAM;
1099 
1100 static void timeout_doall_arg(SSL_SESSION *s, TIMEOUT_PARAM *p)
1101 {
1102     if ((p->time == 0) || (p->time > (s->time + s->timeout))) { /* timeout */
1103         /*
1104          * The reason we don't call SSL_CTX_remove_session() is to save on
1105          * locking overhead
1106          */
1107         (void)lh_SSL_SESSION_delete(p->cache, s);
1108         SSL_SESSION_list_remove(p->ctx, s);
1109         s->not_resumable = 1;
1110         if (p->ctx->remove_session_cb != NULL)
1111             p->ctx->remove_session_cb(p->ctx, s);
1112         SSL_SESSION_free(s);
1113     }
1114 }
1115 
1116 static IMPLEMENT_LHASH_DOALL_ARG_FN(timeout, SSL_SESSION, TIMEOUT_PARAM)
1117 
1118 void SSL_CTX_flush_sessions(SSL_CTX *s, long t)
1119 {
1120     unsigned long i;
1121     TIMEOUT_PARAM tp;
1122 
1123     tp.ctx = s;
1124     tp.cache = s->sessions;
1125     if (tp.cache == NULL)
1126         return;
1127     tp.time = t;
1128     CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
1129     i = CHECKED_LHASH_OF(SSL_SESSION, tp.cache)->down_load;
1130     CHECKED_LHASH_OF(SSL_SESSION, tp.cache)->down_load = 0;
1131     lh_SSL_SESSION_doall_arg(tp.cache, LHASH_DOALL_ARG_FN(timeout),
1132                              TIMEOUT_PARAM, &tp);
1133     CHECKED_LHASH_OF(SSL_SESSION, tp.cache)->down_load = i;
1134     CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
1135 }
1136 
1137 int ssl_clear_bad_session(SSL *s)
1138 {
1139     if ((s->session != NULL) &&
1140         !(s->shutdown & SSL_SENT_SHUTDOWN) &&
1141         !(SSL_in_init(s) || SSL_in_before(s))) {
1142         SSL_CTX_remove_session(s->session_ctx, s->session);
1143         return (1);
1144     } else
1145         return (0);
1146 }
1147 
1148 /* locked by SSL_CTX in the calling function */
1149 static void SSL_SESSION_list_remove(SSL_CTX *ctx, SSL_SESSION *s)
1150 {
1151     if ((s->next == NULL) || (s->prev == NULL))
1152         return;
1153 
1154     if (s->next == (SSL_SESSION *)&(ctx->session_cache_tail)) {
1155         /* last element in list */
1156         if (s->prev == (SSL_SESSION *)&(ctx->session_cache_head)) {
1157             /* only one element in list */
1158             ctx->session_cache_head = NULL;
1159             ctx->session_cache_tail = NULL;
1160         } else {
1161             ctx->session_cache_tail = s->prev;
1162             s->prev->next = (SSL_SESSION *)&(ctx->session_cache_tail);
1163         }
1164     } else {
1165         if (s->prev == (SSL_SESSION *)&(ctx->session_cache_head)) {
1166             /* first element in list */
1167             ctx->session_cache_head = s->next;
1168             s->next->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1169         } else {
1170             /* middle of list */
1171             s->next->prev = s->prev;
1172             s->prev->next = s->next;
1173         }
1174     }
1175     s->prev = s->next = NULL;
1176 }
1177 
1178 static void SSL_SESSION_list_add(SSL_CTX *ctx, SSL_SESSION *s)
1179 {
1180     if ((s->next != NULL) && (s->prev != NULL))
1181         SSL_SESSION_list_remove(ctx, s);
1182 
1183     if (ctx->session_cache_head == NULL) {
1184         ctx->session_cache_head = s;
1185         ctx->session_cache_tail = s;
1186         s->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1187         s->next = (SSL_SESSION *)&(ctx->session_cache_tail);
1188     } else {
1189         s->next = ctx->session_cache_head;
1190         s->next->prev = s;
1191         s->prev = (SSL_SESSION *)&(ctx->session_cache_head);
1192         ctx->session_cache_head = s;
1193     }
1194 }
1195 
1196 void SSL_CTX_sess_set_new_cb(SSL_CTX *ctx,
1197                              int (*cb) (struct ssl_st *ssl,
1198                                         SSL_SESSION *sess))
1199 {
1200     ctx->new_session_cb = cb;
1201 }
1202 
1203 int (*SSL_CTX_sess_get_new_cb(SSL_CTX *ctx)) (SSL *ssl, SSL_SESSION *sess) {
1204     return ctx->new_session_cb;
1205 }
1206 
1207 void SSL_CTX_sess_set_remove_cb(SSL_CTX *ctx,
1208                                 void (*cb) (SSL_CTX *ctx, SSL_SESSION *sess))
1209 {
1210     ctx->remove_session_cb = cb;
1211 }
1212 
1213 void (*SSL_CTX_sess_get_remove_cb(SSL_CTX *ctx)) (SSL_CTX *ctx,
1214                                                   SSL_SESSION *sess) {
1215     return ctx->remove_session_cb;
1216 }
1217 
1218 void SSL_CTX_sess_set_get_cb(SSL_CTX *ctx,
1219                              SSL_SESSION *(*cb) (struct ssl_st *ssl,
1220                                                  unsigned char *data, int len,
1221                                                  int *copy))
1222 {
1223     ctx->get_session_cb = cb;
1224 }
1225 
1226 SSL_SESSION *(*SSL_CTX_sess_get_get_cb(SSL_CTX *ctx)) (SSL *ssl,
1227                                                        unsigned char *data,
1228                                                        int len, int *copy) {
1229     return ctx->get_session_cb;
1230 }
1231 
1232 void SSL_CTX_set_info_callback(SSL_CTX *ctx,
1233                                void (*cb) (const SSL *ssl, int type, int val))
1234 {
1235     ctx->info_callback = cb;
1236 }
1237 
1238 void (*SSL_CTX_get_info_callback(SSL_CTX *ctx)) (const SSL *ssl, int type,
1239                                                  int val) {
1240     return ctx->info_callback;
1241 }
1242 
1243 void SSL_CTX_set_client_cert_cb(SSL_CTX *ctx,
1244                                 int (*cb) (SSL *ssl, X509 **x509,
1245                                            EVP_PKEY **pkey))
1246 {
1247     ctx->client_cert_cb = cb;
1248 }
1249 
1250 int (*SSL_CTX_get_client_cert_cb(SSL_CTX *ctx)) (SSL *ssl, X509 **x509,
1251                                                  EVP_PKEY **pkey) {
1252     return ctx->client_cert_cb;
1253 }
1254 
1255 #ifndef OPENSSL_NO_ENGINE
1256 int SSL_CTX_set_client_cert_engine(SSL_CTX *ctx, ENGINE *e)
1257 {
1258     if (!ENGINE_init(e)) {
1259         SSLerr(SSL_F_SSL_CTX_SET_CLIENT_CERT_ENGINE, ERR_R_ENGINE_LIB);
1260         return 0;
1261     }
1262     if (!ENGINE_get_ssl_client_cert_function(e)) {
1263         SSLerr(SSL_F_SSL_CTX_SET_CLIENT_CERT_ENGINE,
1264                SSL_R_NO_CLIENT_CERT_METHOD);
1265         ENGINE_finish(e);
1266         return 0;
1267     }
1268     ctx->client_cert_engine = e;
1269     return 1;
1270 }
1271 #endif
1272 
1273 void SSL_CTX_set_cookie_generate_cb(SSL_CTX *ctx,
1274                                     int (*cb) (SSL *ssl,
1275                                                unsigned char *cookie,
1276                                                unsigned int *cookie_len))
1277 {
1278     ctx->app_gen_cookie_cb = cb;
1279 }
1280 
1281 void SSL_CTX_set_cookie_verify_cb(SSL_CTX *ctx,
1282                                   int (*cb) (SSL *ssl, unsigned char *cookie,
1283                                              unsigned int cookie_len))
1284 {
1285     ctx->app_verify_cookie_cb = cb;
1286 }
1287 
1288 IMPLEMENT_PEM_rw(SSL_SESSION, SSL_SESSION, PEM_STRING_SSL_SESSION,
1289                  SSL_SESSION)
1290